CLOUDSTACK-9584: Fix Travis to cleanup apt repo before pkg installation

This fixes an env issue that cleans apt repo pkg/cache, before installing new
packages.

Signed-off-by: Rohit Yadav <rohit.yadav@shapeblue.com>

Author: yadvr

tools/travis/before_install.sh

@@ -62,7 +62,8 @@ echo -e "\nCleaning up stale files in /tmp: "
 sudo find /tmp -type f -mtime +2 | grep -v "`sudo lsof | grep /tmp |awk '{print $9}'|sed -e '1 d' |sort |uniq | tr \\n \|`" | xargs sudo rm -vf
 
 echo -e "\nUpdating the system: "
-sudo apt-get -q -y update > /dev/null
+sudo apt-get -y clean
+sudo apt-get -y update > /dev/null
 
 echo -e "\nInstalling MySQL: "